Siblings in MartinLogan's Motion series, so they share a family sound. It comes down to size, output and price.
| Area | Better | Why |
|---|
| Bass | B | MartinLogan 50XTi digs deeper - 50Hz against 115Hz. |
| Amplifier needs | B | MartinLogan 50XTi is more sensitive (94dB vs 86dB), so it goes louder on the same amplifier. |
| Amplifier match | A | MartinLogan Motion 2i is the easier load at 6 ohms; the other is 4 ohms and wants an amplifier rated for it. |
| Size | depends | MartinLogan Motion 2i is easier to place; MartinLogan 50XTi is bigger, which usually goes with fuller bass. Your room decides. |
| Type | depends | A Passive Bookshelf against a Passive Center Channel - a different job rather than a better one. |
| Cabinet | depends | Sealed vs Ported. Sealed is tighter and happier near a wall; ported digs lower but wants space behind it. |
| Expandability | B | MartinLogan 50XTi: bi-amping. |
A MartinLogan Motion 2i B MartinLogan 50XTi
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
MartinLogan 50XTi has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 115Hz anyway, so judge these on the other rows instead. In a large or open-plan room, MartinLogan 50XTi has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, MartinLogan Motion 2i is the easier speaker to get right.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.